Evolution: Biology Study Guide

Evolution

Evolution- change in a population over time
Charles Darwin:
A Naturalist (type of biologist)
Sailed with an explorer on the HMS Beagle to the Galapagos Island in 1831 (22 years old)
He observed
Turtles: On the island they were huge and had to eat food up high (the neck would extend) over time, the shell changed. The ones with the short necks died off because of lack of food
Published the book: Origin of Species By Means of Natural Selection (to beat Wallace)
He’s Catholic
Owen- opposed Darwin for his ideas of evolution because he felt they went against Catholic teaching
Alfred Wallace- worked on the same theory of evolution as Darwin
Thomas Malthus:
“Populations grow faster than the food supply” (competition/survival of the fittest)
Survival of the fittest- people with an advantage will surpass others and live
Lamark:
If you acquired characteristics during your lifetime, those characteristics will be passed onto your offspring
Acquired- developed over your lifetime (lung cancer from smoking)
Inherited- born with it
Law of Use and Disuse- proved Lamark wrong

Natural Selection: mechanism for the change in the population.
When organisms with favorable variations survive and pass these variations to the next generation- natural selection has occurred.
Organisms without these variations are less likely to survive or reproduce.
As a result, each generation consists largely of offspring from parents with these favorable variations

Artificial Selection: Breeding of specific traits in order to produce offspring with those specific traits
Ex: making your child have blue eyes if you don’t (or dog breeding)

Variation: Variation is a marked difference or deviation from the normal or recognized form, function, or structure

Evidence of Evolution
Fossils- our skull expanded (compared to skulls 1,000 years ago) because our brains have developed
Embryology- we all begin the same, but change and evolve for our own purposes
Anatomy- (science by which we study the structures of an organism)
Homologous- structures that have a similar ancestral origin and similar functions
Ex: Forelimbs (front limbs)- arms of humans, bats, whales, and cats

Analogous- Do not have similar ancestral backgrounds but share the same functions
Ex: Butterfly & bird wings
Vestigial structure- a body structure in a present day organism that no longer serves its original purpose, but was probably useful to an ancestor
Biochemistry- The sequence of amino acids in various forms of life demonstrates relationships
The closer a group of animals or plants are, the more amino acids they have in common
Ex: Man & chimp (share 98% of the same amino acids) Men and horse (share 65% of the same amino acids)

Mechanism of Evolution
Populations, not individuals evolve
How a population's genes change:
Gene pool- all of the alleles of the population’s genes in a large pool
Allelic frequency- the percentage of any specific allele in the gene pool
Genetic equilibrium- a population in which the frequency of alleles remain the same over generations
Changes in genetic equilibrium
Mutations- proteins are changed
Genetic drift- alterations of allelic frequency by chance events
Ex: The Amish people
Genetic flow- if people migrate into your region and bring a different gene it will affect the gene pool
ALL EFFECT SMALL POPULATIONS

Types of Natural Selection
Stabilizing selection- favors the average individuals (reduces variation in a population)

Directional selection- favors one of the extreme variations of a trait (can lead to the rapid evolution of a population

Disruptive selection- favors both extreme variations of a trait, resulting in no immediate forms of the trait and leading to the evolution of 2 new species

Speciation: the evolution of a new species (occurs when members of a similar population no longer interbreed to produce offspring in their environment)

Causes of Speciation:
Geographical Isolation- whenever a physical barrier divides a population each small population might adapt to its environment through natural selection and develop its own gene pool
Reproductive isolation- genes are too different to reproduce
Chromosomal isolation- problems in the chromosomes
Rates of Speciation (how fast it happens)
Gradualism- gradual changes
Punctuated- happens in relatively quick bursts
Said by Eldredge and Gould

Patters of Evolution
Divergent evolution- species that once were similar to an ancestral species diverged (spread out and went away)
Ex: Adaptive radiation- when ancestral species evolves into an array of species to fit a number of diverse habitats
Ex: finches
Convergent evolution- a pattern of evolution in which distantly related organisms evolve similar traits
Ex: organ pope cactus- grows in the desert (changes so it can survive)

Adaptations- any variation that aids an organism’s chance of survival in its environment
Two types of adaptations:
Structural- physically see
Changes in the anatomy
Ex: mole rat- long claws and sharp teeth to make up for it being blind
Mimicry- an organism tries to be like another more dangerous organism
Camouflage- blends in with its surroundings
Physiological- internal environment
Ex: bacteria- by making different proteins it has adapted to the medicine we’ve developed to kill off their species

Fill Ins
List the 3 different types of Natural Selection? Give an example of each
1. ______________ Example: __________________

2. ______________ Example: __________________

3. ______________ Example: __________________

What are the 2 patterns of evolution? Give an example
1. ______________
Example: __________________

2. ______________
Example: __________________

What are the possible causes of speciation? Give an example of each cause
1. ______________
Example: __________________

2. ______________ Example: __________________

3. ______________ Example: __________________

What are the two theories regarding the rate of speciation?
1. ______________

2. ______________

What are the two main categories of adaptation?
1. ______________

2. ______________

What are the two types of structural adaptation. Give an example
1. ______________
Example: __________________

2. ______________
Example: __________________

Give an example of physiologic adaptation
1. ______________

Name 3 different species Darwin studied on the Galapagos? Describe any interesting facts
1. ______________
Fact: _____________________

2. ______________
Fact: _____________________

3. _____________
Fact:______________________

Answer Key
List the 3 different types of Natural Selection? Give an example of each
Stabilizing selection Example: a population of spiders in which average size is a survival advantage.

Directional selection Example: wood peckers feeding on insects deep within the tree bark- birds with long beaks have an advantage over short or average size beaked
Disruptive selection Example: white-shelled limpets cannot be seen on light rocks, dark colored limpets camouflage with the dark rocks, tan-colored limpets can be seen on either the light or dark backgrounds.

What are the 2 patterns of evolution? Give an example
Divergent evolution
Example: (adaptive radiation, when ancestral species evolves into an array of species to fit a number of diverse habitats) An example of that would be the finches.
Covergent evolution
Example: organ pope cactus.

What are the possible causes of speciation? Give an example of each cause
Geographical Isolation
Example: If small populations of tree frogs were geographically isolated, they would no longer be able to interbreed and exchange genes.

Reproductive isolation Example: if one population of tree frogs mates in the fall, and another mates in the summer

Chromosomal isolation Example: When a Polyploid mates with an individual of the normal species, the offspring will not develop normally because of difference in chromosome numbers

What are the two theories regarding the rate of speciation?
Gradualism
Punctuated

What are the two main categories of adaptation?
Structural
Physiological

What are the two types of structural adaptation. Give an example
Mimicry
Example: yellow jacket wasp and a harmless syrphid fly- the colors and body shape are similar, so predators avoid both.
Camouflage
Example: leaf frog

Give an example of physiologic adaptation
Bacteria- by making different proteins it has adapted to the medicine we’ve developed to kill off their species

Name 3 different species Darwin studied on the Galapagos? Describe any interesting facts
Beak of the Galápagos finches
Fact: They have adapted to feed on cacti
Tortoises
Fact: largest on Earth, differing from other tortoises in body size and shape
Marine iguanas
Fact: ate algae from the ocean, an unusual food source for reptiles. Large claws help them cling to slippery rocks.